Parasitic Drain- Dome but effects radio and info display

[ggc]

My parents have a 2000 Lexus RX300.  About 6 months ago it developed a parasitic drain that would completely drain the battery if it sat for a few days.  I tested the current draw for all the fuses under the hood and found the DOME fuse was consistently drawing about 0.5 amps with the doors closed and the interior lights off.  I removed the DOME fuse and the battery has maintained its charge after sitting for several weeks.  Odd thing is that when I removed the DOME fuse, we lost power to the radio and the center information panel.  I don't know why the radio and information panel would be effected by the DOME circuit.  Is there a component that would interconnect the radio/information center to the Dome circuit? Thanks, Gilbert

[R3X00]

I know this reply is way late. XD

 

But it's likely an interconnected Module/load on the circuit. Similar situation with my '03 today, d/c'd the Dome fuse dropped draw by nearly .4 amps.

 

I'll know more on Monday day when I return to my shop, and can get circuit printout.

Edited October 16, 2022 by R3X00
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[Dafo]

Did you ever figure out how these two circuits connect? I have the same drain and would love to pull the dome fuse but still have the radio on. 

[Geer]

2014 ES300h.  (311k on original battery) Just had the hybrid battery replaced and now the dome light doesn't work when door opens.  The dome light can still be turned on with the ceiling mounted switch though. the floor lights do function when the door is opened. 

Crazy thing is, just like you, Ive lost all functionality of the radio, nav, backup camera, bluetooth and the screen is dead. HVAC still working.

Could this relate to your dome light issue? What fuse number controls the doom light? engine bay or interior fuse box? Dafo, any ideas?

I've heard there is a anti-theft feature that when the vehicle logs a power disconnect, the radio system and functions associated shuts down. Could this also be the issue with your car since your battery drained sitting too long?

[RX400h]

Quote

1. DOME Circuit and Parasitic Drain:

   • The DOME circuit typically controls interior lights, including the dome light, map lights, and other cabin illumination.
   • When you removed the DOME fuse, it interrupted the power supply to these lights, which explains why the battery drain ceased.

2. Radio and Information Panel Connection:

   • The unexpected part is how removing the DOME fuse affected the radio and center information panel.
   • While it might seem unrelated, there could be an interconnected module or shared component between these systems.
   • Some possibilities include:
     • Shared Ground: The DOME circuit and radio/panel might share a common ground point. Disrupting the DOME circuit could impact the ground connection for other components.
     • Control Module: There could be a control module that manages both the DOME circuit and the radio/panel. If this module malfunctions, it might cause unexpected behavior.
     • Wiring: Faulty wiring or a short circuit could inadvertently link these systems.

3. Further Investigation:

   • To pinpoint the exact cause, consider the following steps:
     • Circuit Diagram: Obtain a wiring diagram for your vehicle. This will show the connections between various components.
     • Scan for Fault Codes: Use an OBD-II scanner to check for any diagnostic trouble codes (DTCs) related to the radio or information panel.
     • Inspect Wiring: Physically inspect the wiring harnesses and connectors associated with the DOME circuit, radio, and information panel.
     • Professional Help: If you’re unable to identify the issue, consult a professional mechanic or an auto electrician (auto-electric shop). They can perform more in-depth diagnostics.

Remember that automotive electrical systems can be intricate, and seemingly unrelated components may interact in unexpected ways. Investigating systematically will help uncover the underlying cause. Good luck!

 

[Geer]

Thanks Dave for your input,

Funny thing is, the all the interior lights are now functioning, go figure. When I failed to find any blown fuses, I reported back to third party refurbished hybrid battery installer. They were at a loss and weren't interested in sending their tech back to resolve the issue.  They said "go to the dealership" we will stand behind our work. The dealership confirmed (after a $180 diagnostic fee) there is power to the radio and no ground issues. It is indeed dead. Quote from dealer, $2910.00 for a new radio + lcd screen. No refurbished unit in their back stock.

So this company is on the hook for $3090.00, if they honor their service. I'm not going to expect them to pay for a brand new radio to replace a ten year old one but I do expect to be reimbursed for the dealer diagnosis fee, the cost of a used unit and installation fee.

Jury is still out as I fight that battle.  Just a tip for those replacing a broken radio, there is a number below the volume control to left, for me its a 6 digits. This should match replacement unit or risk non compatibility issues.

Gil & Dafo, I did find that fuses associated with radio functions do indeed control other electronics such as the back up lights and exterior door lock touch sensor.